Owners of vending machines face a dilemma: increasing the number of service calls increases the chances that a vending machine will function properly and have adequate inventory at any given time, but increases costs, while reducing the number of service calls reduces costs but increases the chances of lost revenues through malfunction or out-of-stock conditions.
A challenge to the industry has been to find the frequency of service calls which maximizes profits, i.e., to balance the increased cost of additional service calls with the increased revenue of additional sales.
Two approaches have been used: improving the quality of information with respect to the current status of inventory at a given vending machine (or a network of such machines), and improving the quality of analysis of such information in order to improve predictions of the need for future service calls.
An example of the first approach may be found in U.S. Pat. No. 5,207,784, issued on May 4, 1993 to Schwartzendruber for “Vending Machine with Monitoring System”, and assigned to Skywire, LP (and therefore commonly owned with the instant application). As described therein, a vending machine is equipped with means for determining current inventory and other status and transmitting that information to a remote location to aid in scheduling service calls. The technique described in the '784 patent requires two-way communication between the vending machine and a remote monitoring center. Providing similar capabilities using one-way communications can reduce cost.
The instant invention provides advanced information gathering, transmitting and analysis capabilities.
In describing the state of the art and the invention, it will be helpful to begin with a generalized description of a typical vending machine and how it is typically stocked and serviced.
Vending machines typically comprise means for storing goods to be dispensed, cash receiving means for receiving cash deposits from a user, cash calculating means for determining the value of the cash deposited by the user, good pricing means for determining the price of a particular good selected by the user, comparator means for comparing the value of the cash deposited by the user with the price of the good selected by the user, and dispensing apparatus for dispensing the selected good if the user has deposited sufficient cash and for dispensing cash if change is required. Vending machines may also include means for detecting certain conditions, such as out-of-stock, jam or unauthorized entry. On modern machines, the above functions are controlled electronically, typically by 120 VAC controls.
A modern vending machine can have a variable number of product selection buttons, a variable number of supply columns, supply columns of different capacities, and the capability to assign columns to buttons. For example, multiple supply columns may be assigned to the same button. Typically, each selection button is associated with a single product, of which multiple items are available for sale. Thus, it is possible to provide various capacities for various products.
By way of example, a typical cold drink dispensing vending machine has from six to twelve selection buttons, but from six to twenty supply columns, with each supply column having a capacity of from 15 to 65 items of the product.
The rate of sale of any given product may vary from vending machine to vending machine, and may also vary at a particular machine over a period of time. The rate of sale for a particular product is referred to as its “velocity”. Where a product is stored in multiple supply columns, the total velocity of the product is the sum of the velocity of each of such supply columns.
Vendors (the owners of vending machines) typically employ maintenance personnel who periodically make service calls to physically inspect the machine to determine inventory status, restock if necessary, correct any faults (such as a jam) and collect the cash deposited by users.
If the maintenance personnel arrive when there is sufficient inventory and no fault, the cost of the maintenance trip is wasted; if they arrive after inventory has been exhausted or a fault has gone unremedied, sales may have been lost.
Because of the inherent delay in scheduling restocking of inventory, typically, inventory would not be allowed to drop to zero before initiating the restocking process, but rather a “resupply trigger level”, would be chosen at a level designed to permit time for restocking before the inventory is exhausted.
If a product's inventory level at a given time and velocity are known for a given vending machine, it is possible to project the inventory level at a future time. This projection allows determination of a restocking schedule and route, with the goal being to optimize the restocking interval. Ideally, the number and capacity of supply columns would be chosen such that each product inventory would approach the resupply trigger level at the same time.
Finally, it is common for vending machines to be managed as a group, it being more efficient and economical to stock and service a network of such machines than a single machine.